1. Field of the Invention
The present invention relates to a new and improved lathe and, more particularly, pertains to trimming and truing slip rings of alternators with a miniaturized portable lathe.
2. Description of the Prior Art
As will become evident from the descriptions herein after, on certain Leece-Nevelle alternators that use external slip rings, excessive slip ring run-out causes premature voltage regulator and/or brush failure and bearing failure due to the heat generated by brush bounce. By reducing or eliminating excessive slip ring run-out, the life of an alternator will be greatly extended.
During there building process the slip ring end frame bearing must be removed from the rotor and replaced. To accomplish this step the slip ring must be unsoldered from the rotor coil leads and removed with a puller. The slip ring end frame bearing is removed and the new bearing then installed on the rotor shaft. At this point either the original slip ring is reinstalled on the rotor or a new slip ring is installed and soldered into place. Most certainly for the reinstallation and certainly for the installation of the new slip ring a truing of the slip ring is necessary once it has been pressed on the rotor shaft. This can be accomplished by placing the rotor in the lathe and using a live center or a steady-rest to true the slip ring. Using the live center on the slip ring end of the rotor shaft assumes that the tail shaft of the rotor is true, which is often not the case. Once turned, the slip ring will be out of round. Use of the steady-rest to secure the slip ring end bearing while turning the rotor will provide better results, but is difficult and time consuming to set up.
By using the lathe of the present invention, the truing of the slip ring can be accomplished after the alternator has been assembled minus the brush holder and/or brush holder and voltage regulator. With this process the miniature lathe is attached to the slip ring end frame by means of clamps, and is automatically centered. The cutting tool of the miniature lathe is adjusted to the proper cutting depth and the entire assembly placed on an alternator test bench. The alternator and miniature lathe is then fixed to the test bench and the alternator is hooked up to the drive belt. The alternator is then spun in a counterclockwise rotation. The manual drive of the miniature lathe is engaged and the slip ring is then cut. Depending upon the amount of run-out of the slip ring, the miniature lathe will probably need to be readjusted and engaged again until the entire surface of the slip ring has been cut and trued. By cutting and truing the slip ring after the alternator has been assembled, the rebuilder gets the advantage of having both the drive end frame and the slip ring end bearings in place to accurately center the rotor and the slip ring for the cutting process. In addition the use of the miniature lathe will shorten the rebuild time.
In summary, the use of this invention will greatly refine rebuilding of those Leece-Neville alternators having external slip ring placement The finished product will be a more accurate representation of the rebuilders craft.
The use of lathes is known in the prior art. More specifically, lathes heretofore devised and utilized for the purpose of trimming and truing rotating cylinders are known to consist basically of familiar, expected, and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which has been developed for the fulfillment of countless objectives and requirements.
The prior art discloses a large number of lathes. By way of example, U.S. Pat. No. 4,328,722 to Wohlhaupter discloses apparatus for facing and internal turning. U.S. Pat. No. 4,355,533 to Church discloses a portable turning tool. U.S. Pat. No. 4,506,570 to Wood discloses a lathe apparatus especially designed for brake drums and discs. Lastly, U.S. Pat. No. 5,009,728 to Thiem discloses a swing arm brake lathe.
In this respect, the lathe according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of trimming and truing slip rings of alternators.
Therefore, it can be appreciated that there exists a continuing need for a new and improved lathe which can be used for trimming and truing slip rings of alternators. In this regard, the present invention substantially fulfills this need.